JP2016160787A - Starter of engine, starting method, and ship including starter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent surging of a compressor, enable engine starting with a small amount of power consumption while rotatably driving the compressor with an electric motor, and reduce an amount of exhaust smoke in engine starting.SOLUTION: A starter 2 includes: a bypass passage 44 connecting a compressed air outlet of a compressor 26 of an electric exhaust supercharger 24 and an exhaust inlet of an exhaust turbine 25; a bypass valve 45 opening/closing the bypass passage 44; and a starting control unit 48 that opens the bypass valve 45 and rotates the compressor 26 of the electric exhaust supercharger 24 by an electric motor 28, before starting an engine 1, and then closes the bypass valve 45 at timing according to starting of the engine 1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a marine vessel equipped with an engine starting device, a starting method, and a starting device suitable for a large marine two-cycle diesel engine.

  As disclosed in Patent Document 1, in a turbocharger equipped in a large marine two-cycle diesel engine or the like, an electric exhaust supercharger provided by directly connecting an electric motor also serving as a generator to a rotor shaft of the supercharger Machine (hybrid supercharger) has been put into practical use.

  This is for energizing the rotation of the rotor shaft by following the engine output of the engine body during low-load operation of the engine or when the output increases, thereby preventing a temporary shortage of air supply of the engine body.

JP 2010-127239 A

  In a large marine two-cycle diesel engine equipped with such an electric exhaust supercharger, the compressor of the supercharger can be controlled by increasing the rotational speed of the rotor shaft of the supercharger in advance with an electric motor before starting the engine. Driven to generate compressed air, this compressed air can be sent to the scavenging chamber to increase the pressure in the scavenging chamber. In addition, the rotational speed of the compressor can be quickly increased as the engine is started to suppress the generation of exhaust smoke due to a temporary shortage of air.

  This makes it possible to use an electric auxiliary blower (blower) that has been installed in the scavenging chamber in the past to send air into the scavenging chamber in areas where it is not possible to improve the scavenging air pressure due to the turbocharger It is expected that the engine can be started without any problem, the air supply amount at the start of the engine is increased to improve the combustion state, and the amount of exhaust smoke at the start is reduced.

  However, in a uniflow marine large two-cycle diesel engine equipped with an exhaust valve that is driven to open and close by hydraulic pressure, the exhaust valves of each cylinder are all closed due to loss of the drive hydraulic pressure before the engine is started. If the turbocharger is rotated before the engine is started, the compressed air discharged from the turbocharger compressor remains in the scavenging chamber and cannot flow constantly. There was a problem that occurred.

  Also, before starting the engine, exhaust gas does not flow into the exhaust turbine of the turbocharger and the rotational driving force due to the energy of the exhaust gas cannot be obtained, so the rotor shaft of the turbocharger must be rotated only by the output of the motor. There is a problem that the required power of the electric motor becomes large due to the failure.

  Further, conventionally, the pressure of the scavenging chamber at the time of starting the engine is increased by the electric auxiliary blower. However, the installation of the electric auxiliary blower complicates the configuration of the engine starting device, and the power consumption cannot be ignored.

  The present invention has been made in view of such circumstances, and enables engine startup with low power consumption while rotating the compressor with an electric motor while preventing surging of the compressor, and at the time of engine startup. It is an object of the present invention to provide an engine starting device, a starting method, and a ship equipped with the starting device capable of reducing the amount of exhaust smoke.

  In order to solve the above problems, the present invention employs the following means.

  That is, the engine starter according to the first aspect of the present invention is an engine starter provided with an electric exhaust supercharger that urges the rotation of the compressor with an electric motor, and includes an air outlet of the compressor and an exhaust turbine. A bypass passage that connects to an exhaust inlet, a bypass valve that opens and closes the bypass passage, and before starting the engine, opens the bypass valve and rotates the compressor by the electric motor to respond to the start of the engine And an activation control unit that closes the bypass valve at a predetermined timing.

  According to the engine starter having the above-described configuration, before starting the engine, the start control unit opens the bypass valve and rotates the compressor of the electric exhaust supercharger with the electric motor. The air compressed by the compressor flows from the compressed air outlet of the compressor through the bypass passage to the exhaust inlet of the exhaust turbine.

  Therefore, in a uniflow type two-cycle engine, even if the exhaust valve is closed before the engine is started and the compressed air from the compressor cannot flow into the scavenging chamber, the compressed air loses its place and the compressor Does not cause surging. And the rotational speed of the compressor required in order to ensure sufficient scavenging air pressure to suppress smoke generation when the engine is started can be maintained.

  In addition, power is required to rotate the compressor with an electric motor to generate compressed air, but the generated compressed air is supplied to the exhaust turbine through a bypass passage, and rotates the exhaust turbine and is coaxial with the exhaust turbine. The compressor above is also driven to rotate. For this reason, the compressor can be driven with a small force, and the required power of the electric motor can be greatly reduced as compared with the case where no bypass passage is provided.

  Next, the engine is started. In a large marine two-cycle diesel engine, compressed air for start-up can be introduced into a combustion cylinder in which the piston is in the expansion stroke position, and the piston can be pushed down to start the engine.

  Since the compressor of the electric supercharger is rotated in advance by the electric motor before the engine is started, the rotational speed of the compressor can be quickly raised at the same time as the engine is started to sufficiently cover the air amount at the time of starting the engine.

  For this reason, the pressure of the scavenging chamber can be increased and the two-cycle engine can be started with less power consumption. Thereby, it is not necessary to increase the pressure of the scavenging chamber using the electric auxiliary blower as in the conventional case, and the electric auxiliary blower can be made unnecessary. Moreover, it is possible to improve the combustion state by increasing the amount of combustion air when starting the engine, and to reduce the amount of exhaust smoke.

  The start control unit closes the bypass valve at a timing according to the start of the engine. As a result, the compressed air generated by the compressor is not supplied to the exhaust turbine, and the entire amount of compressed air is sent to the engine (scavenging chamber) to shift to normal operation.

  When the engine is a two-cycle engine, it is preferable that compressed air of the compressor driven by the electric motor is supplied to the bypass passage and the scavenging chamber of the engine before the engine is started.

  With the above configuration, when the compressor is driven by the electric motor before starting the engine, the pressure of the compressed air discharged from the compressor is applied to the scavenging chamber, and the scavenging chamber is pressurized to the pressure of the compressed air outlet of the compressor. For this reason, while raising the pressure of a scavenging chamber from atmospheric pressure and ensuring sufficient air quantity required for engine starting, generation | occurrence | production of exhaust smoke by temporary shortage of air quantity can be suppressed.

When the engine is a two-cycle engine, the timing for closing the bypass valve is preferably immediately after starting the two-cycle engine.
Thereby, it is possible to reliably prevent the compressor from surging due to the influence of compressed air that cannot flow into the scavenging chamber before the engine is started.

Moreover, the ship which concerns on the 2nd aspect of this invention was equipped with the starting device of one of said engines.
According to this ship, when the engine is a uniflow type two-cycle engine, even if the exhaust valve remains closed before the engine is started, it does not cause surging in the compressor and consumes less power. The engine can be started.
Moreover, since the pressure in the scavenging chamber can be increased when the engine is started, the combustion state at the time of starting the engine can be improved and the amount of exhaust smoke can be reduced.

  An engine starting method according to the third aspect of the present invention is an engine starting method including an electric exhaust supercharger that urges rotation of a compressor by an electric motor, and the electric motor is started before the engine is started. Rotating the compressor of the electric exhaust supercharger and supplying a compressed air discharged from the compressor to the exhaust turbine, an engine starting step for starting the engine, and the engine starting And a supercharging start step of supplying the compressed air to the engine side at a timing.

  In the above engine starting method, first, in the supercharging preparation step, the compressor is rotated by the electric motor, and the compressed air discharged from the compressor is supplied to the exhaust turbine. Thereby, the air compressed by the compressor is supplied to the exhaust inlet of the exhaust turbine, and the scavenging chamber is pressurized to the pressure of the compressed air outlet of the compressor.

  Therefore, in a uniflow type two-cycle engine, even if the exhaust valve is closed before the engine is started and the compressed air from the compressor cannot flow into the scavenging chamber, the compressed air loses its place and the compressor Does not cause surging. And the rotational speed of the compressor required in order to ensure sufficient scavenging air pressure to suppress smoke generation when the engine is started can be maintained.

  In addition, power is required to rotate the compressor with an electric motor to generate compressed air, but the generated compressed air is supplied to the exhaust turbine to rotate the exhaust turbine, and the compressor is coaxial with the exhaust turbine. Also drives to rotate. For this reason, the compressor can be driven with a small force, and the required power of the electric motor can be greatly reduced as compared with the case where compressed air is not supplied to the exhaust turbine.

  Next, the engine is started in the engine starting step. Since the compressor rotation speed is increased in advance in the supercharging preparation step, in the two-cycle engine, the scavenging chamber pressure is quickly increased simultaneously with the engine starting. It is possible to supply the engine with sufficient combustion air from the scavenging chamber and to start it well.

  Therefore, the two-stroke engine can be started by increasing the pressure in the scavenging chamber with low power consumption. Thereby, it is not necessary to increase the pressure of the scavenging chamber using the electric auxiliary blower as in the conventional case, and the electric auxiliary blower can be made unnecessary. Moreover, it is possible to improve the combustion state by increasing the amount of combustion air when starting the engine, and to reduce the amount of exhaust smoke.

  Next, in the supercharging start step, the compressed air generated by the compressor is supplied to the engine side at a timing corresponding to the start of the engine. Thereby, compressed air is sent to an engine (scavenging chamber) and shifts to normal operation.

  As described above, according to the engine starting device, the starting method, and the ship provided with the starting device according to the present invention, the engine can be started with low power consumption while rotating the compressor with an electric motor while preventing the compressor from surging. This makes it possible to reduce the amount of exhaust smoke when the engine is started.

It is a schematic block diagram of the marine large-sized diesel engine and starting device which show embodiment of this invention. It is a figure which shows the flow of control of a starting device with a flowchart. It is a diagram which shows the relationship between the opening / closing timing of a bypass valve, the rotational speed of a compressor, the pressure of a scavenging chamber, and the air quantity which flows into an engine.

  Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a large marine diesel engine 1 and a starter 2 showing an embodiment of the present invention.
The marine large diesel engine 1 (engine) is, for example, a uniflow type two-cycle engine, and includes a plurality of combustion cylinders 4, an exhaust static pressure pipe 5, and a scavenging chamber 6. A crankshaft 8 is pivotally supported below each combustion cylinder 4, a piston 9 inserted into the combustion cylinder 4 is connected to the crankshaft 8 by a connecting rod 10, and the reciprocating motion of the piston 9 in the combustion cylinder 4 is the crankshaft. It is converted into a rotational motion of 8 and becomes the output of the marine large diesel engine 1.

  A scavenging port 12 communicating with the inside of the scavenging chamber 6 is provided in the vicinity of the lower portion of each combustion cylinder 4, and an exhaust port 13 connected to the exhaust static pressure pipe 5 and an exhaust valve 14 for opening and closing the same are provided above the combustion cylinder 4. And are provided. Each exhaust valve 14 is always urged in the valve closing direction by a valve spring 15 (generally an air spring), and is opened by hydraulic pressure.

  An electric exhaust supercharger 24 is attached to the large marine diesel engine 1. The electric exhaust supercharger 24 is configured such that an exhaust turbine 25 and a compressor 26 rotate integrally with each other via a rotor shaft 27. 27) is energized.

  An exhaust gas supply pipe 31 extending from the exhaust static pressure pipe 5 is connected to an exhaust inlet of the exhaust turbine 25, and an exhaust gas discharge pipe 32 extends from the exhaust outlet of the exhaust turbine 25. A compressed air pipe 35 extending from the compressed air outlet of the compressor 26 is connected to an air cooler 37 attached to the scavenging chamber 6.

  Further, a bypass passage 44 that connects the compressed air outlet of the compressor 26 and the exhaust inlet of the exhaust turbine 25 is disposed, and a bypass valve 45 is connected to the bypass passage 44. The bypass valve 45 is an open / close valve that opens and closes the bypass passage 44. The bypass passage 44 also communicates with the scavenging chamber 6 via the compressed air pipe 35. The bypass passage 44 may be branched from the compressed air pipe 35 and connected to the exhaust inlet of the exhaust turbine 25.

  The exhaust gas discharged when the large marine diesel engine 1 is operated is supplied to the exhaust turbine 25 through the exhaust static pressure pipe 5 and the exhaust gas supply pipe 31, and the exhaust turbine 25 is rotationally driven at a high speed. The exhaust gas that has finished driving the exhaust turbine 25 is discharged from the exhaust gas discharge pipe 32 to the outside.

  When the exhaust turbine 25 rotates, the compressor 26 also rotates, the atmosphere is compressed by the compressor 26, this compressed air is supplied from the compressed air pipe 35 to the scavenging chamber 6 through the air cooler 37, and each combustion is performed from the scavenging port 12. It is supplied to the cylinder 4. Thus, by compressing the intake air by using the energy of the exhaust gas, the air filling rate to each combustion cylinder 4 can be increased and the engine efficiency can be improved.

When the large marine diesel engine 1 is operated under a load state of approximately 30% or more, the exhaust turbine 25 can be rotationally driven by the energy of the exhaust gas to operate the compressor 26 as described above.
However, when the engine is started or when the engine is operated under a load of 30% or less, the amount of exhaust gas discharged is small, so that the compressor 26 cannot be operated sufficiently. For this reason, the rotation of the compressor 26 is urged by the electric motor 28 to prevent the air filling rate from being lowered.

  The starting device 2 provided in the large marine diesel engine 1 includes an activation control unit 48, a bypass passage 44, and a bypass valve 45. The activation control unit 48 is, for example, a control unit (CPU), and sends operation signals A1 and A2 to the electric motor 28 of the electric exhaust supercharger 24 and the bypass valve 45, respectively.

Next, an activation method in the activation device 2 and a control flow by the activation control unit 48 will be described with reference to FIGS. 2 and 3.
FIG. 2 is a flowchart showing the flow of control of the starter 2, and FIG. 3 shows the opening / closing timing of the bypass valve 45, the rotational speed of the compressor 26, the pressure in the scavenging chamber 6, and the amount of air flowing through the marine large diesel engine 1. FIG.

This starting method includes a “supercharging preparation step”, an “engine starting step”, and a “supercharging start step”.
First, after the start of the control, an engine start command is issued (step S1 in FIG. 2, point A in FIG. 3), and in response to this, the start control unit 48 opens the bypass valve 45 (step S2), and the electric motor 28 is turned on. Operate (step S3). Steps S2 and S3 are “supercharging preparation steps”. As a result, the compressor 26 starts rotating at a constant rotational speed N1.

  The timing for opening the bypass valve 45 and the timing for operating the motor 28 may be in a stage before point A in FIG. 3, but the motor 28 is operated before the bypass valve 45 is opened. The air compressed by the compressor 26 is sent to the scavenging chamber 6 and the compressor 26 causes surging as described above, which is not preferable.

  The air compressed by the compressor 26 driven by the electric motor 28 flows from the compressed air outlet of the compressor 26 to the exhaust inlet of the exhaust turbine 25 through the bypass passage 44. Further, since the compressed air outlet of the compressor 26 communicates with the scavenging chamber 6, the pressure of the compressed air discharged from the compressor 26 is also applied to the scavenging chamber 6, and the pressure of the scavenging chamber 6 is changed from the atmospheric pressure in FIG. It rises to P1 shown.

  In a uniflow type two-cycle engine such as the large marine diesel engine 1, even if the exhaust valve 14 is closed before the engine is started and the compressed air from the compressor 26 cannot flow into the scavenging chamber 6, the compression is performed. Since all the air flows to the exhaust turbine 25, the compressor 26 does not cause surging. Moreover, the rotational speed of the compressor 26 can be kept high.

  In addition, power is required to rotate the compressor 26 with the electric motor 28 to generate compressed air, but the generated compressed air is supplied to the exhaust turbine 25 via the bypass passage 44 and rotates the exhaust turbine 25. The compressor 26 coaxial with the exhaust turbine 25 is also driven to rotate. For this reason, the compressor 26 can be driven with a small force, and the required power of the electric motor 28 can be reduced as compared with the case where the bypass passage 44 is not provided.

  Next, the large marine diesel engine 1 is activated (step S4 in FIG. 2, point B in FIG. 3). In the large marine diesel engine 1, the start-up compressed air is introduced into the combustion cylinder 4 and the piston 9 is pushed down to start the engine. This step S4 is an engine starting step.

  Since the compressor 26 of the electric exhaust supercharger 24 is rotated in advance by the electric motor 28 before this engine starting step, the rotational speed of the compressor 26 is quickly raised simultaneously with the starting of the engine 1, and the amount of air at the time of starting the engine. Can be fully covered.

  Therefore, the marine large diesel engine 1 can be started by increasing the pressure in the scavenging chamber 6 with less power consumption. Thereby, it is not necessary to increase the pressure in the scavenging chamber 6 using an electric auxiliary blower as in the prior art, and the electric auxiliary blower can be dispensed with. Moreover, it is possible to improve the combustion state by increasing the amount of combustion air when starting the engine, and to reduce the amount of exhaust smoke discharged when starting the engine.

  When the large marine diesel engine 1 is started, the exhaust turbine 25 is rotationally driven by both the energy of the exhaust gas discharged from each combustion cylinder 4 and the driving force of the electric motor 28, so the rotational speed of the compressor 26 is N1. As a result, the air is increased from N1 to N2, so that a large amount of air is supercharged in the scavenging chamber 6, and the scavenging chamber pressure is increased from P1 to P2. Further, the intake air amount of the large marine diesel engine 1 increases from 0 to V1.

  The bypass valve 45 is closed at a timing corresponding to the start of the marine large diesel engine 1 (step S5 in FIG. 2 and point C in FIG. 3). When the bypass valve 45 is closed, the compressed air generated by the compressor 26 is not supplied to the exhaust turbine 25, and the entire amount of the compressed air is sent to the scavenging chamber 6 to shift to the normal operation by the electric exhaust supercharger 24. . For this reason, this step S5 becomes a supercharging start step.

  Further, the rotational speed of the compressor 26 is reduced to an intermediate value between N2 and N1 when the bypass valve 45 is closed and the compressed air of the compressor 26 is not supplied to the exhaust turbine 25. On the other hand, the pressure of the scavenging chamber 6 rises from P2 to P3 when the entire amount of compressed air generated by the compressor 26 is sent to the scavenging chamber 6 as described above, and the intake air amount of the marine large diesel engine 1 is V1. From V2 to V2 and normal operation is started.

  In FIG. 3, the timing (point C) for closing the bypass valve 45 is set immediately after the start timing (point B) of the marine large diesel engine 1. For example, the bypass valve 45 is closed several seconds after the start-up compressed air is supplied to the combustion cylinder 4 from the start-up air input device to start the engine. Thereby, it is possible to reliably prevent the compressor 26 from surging due to the influence of compressed air that cannot flow into the scavenging chamber 6 before the engine is started.

  As described above, according to the engine starting device 2, the starting method, and the ship provided with the starting device 2 according to the present invention, the compressor is driven by the electric motor 28 while preventing the surging of the compressor 26 in the electric exhaust supercharger 24. While rotating the engine 26, the engine can be started with low power consumption, and the amount of exhaust smoke when the engine is started can be reduced.

  It should be noted that the present invention is not limited to the configuration of the above-described embodiment, and can be appropriately modified or improved within a scope not departing from the gist of the present invention. Are also included in the scope of rights of the present invention.

  For example, in the above embodiment, an example in which the present invention is applied to a large marine diesel engine mounted as a main engine of a marine vessel has been described. However, the present invention can be applied not only to marine engines but also to engines for other uses. . Further, the present invention can be applied not only to a two-cycle engine but also to a four-cycle engine.

1 Marine Diesel Engine (Engine)
2 Starter 4 Combustion cylinder 5 Exhaust static pressure pipe 6 Scavenging chamber 12 Scavenging port 13 Exhaust port 14 Exhaust valve 24 Electric exhaust supercharger 25 Exhaust turbine 26 Compressor 27 Rotor shaft 28 Electric motor 44 Bypass passage 45 Bypass valve 48 Start control unit S2, S3 Supercharging preparation step S4 Engine starting step S5 Supercharging start step

Claims (5)

An engine starter equipped with an electric exhaust supercharger that urges the rotation of a compressor with an electric motor,
A bypass passage connecting the compressed air outlet of the compressor and the exhaust inlet of the exhaust turbine;
A bypass valve for opening and closing the bypass passage;
Before starting the engine, open the bypass valve, rotate the compressor by the electric motor, and close the bypass valve at a timing according to the start of the engine,
An engine starting device comprising:   The engine according to claim 1, wherein the engine is a two-cycle engine, and compressed air of the compressor driven by the electric motor is supplied to the bypass passage and the scavenging chamber of the engine before the engine is started. Starting device.   The engine starting device according to claim 1 or 2, wherein the engine is a two-cycle engine, and the timing for closing the bypass valve is immediately after the two-cycle engine is started.   A ship provided with the engine starting device according to any one of claims 1 to 3. A method for starting an engine including an electric exhaust supercharger that urges rotation of a compressor with an electric motor,
Before starting the engine, a supercharging preparation step of rotating the compressor of the electric exhaust supercharger by the electric motor and flowing compressed air discharged from the compressor to the exhaust turbine side;
An engine start step for starting the engine;
A supercharging start step for flowing the compressed air to the engine side at a timing according to the start of the engine;
An engine starting method comprising:

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